Various approaches for providing light absorbing materials have been proposed. A popular approach is the incorporation of a light trapping layer that consists of noble metal nanoparticles onto a photovoltaic device. Nanostructured plasmonic interfaces for this purpose have been fabricated by using lithography, vapor deposition, de-wetting of thin metal films by ns and fs pulsed lasers, and wet chemistry using self-assembled monolayers. Economical scale-up and adaption of such processes to fabricate interfaces with multiple species/shapes/sizes in a controllable and repeatable fashion are not straightforward.
Light trapping and photocurrent enhancement (PE) by plasmonic interfaces have been documented. There have been several methods reported in the literature to create plasmonic interfaces, such as electron beam lithography [H. A. Atwater and A. Polman, “Plasmonics for improved photovoltaic devices,” Nature Materials, vol. 9, no. 3, pp. 205-13, March 2010], thermal evaporation [K. Nakayama, K. Tanabe, and H. A. Atwater, “Plasmonic nanoparticle enhanced light absorption in GaAs solar cells,” Applied Physics Letters, vol. 93, no. 12, pp. 121904-121904-3, 2008], nanoimprinting lithography [V. E. Ferry, M. A. Verschuuren, H. B. T. Li, E. Verhagen, R. J. Walters, R. E. I. Schropp, H. A. Atwater, and A. Polman, “Light trapping in ultrathin plasmonic solar cells.,” Optics Express, vol. 18, no. 102, pp. A237-45, July 2010], and ns and fs pulsed laser patterning of ultra-thin films [A. I. Kuznetsov, J. Koch, and B. N. Chichkov, “Nanostructuring of thin gold films by femtosecond lasers,” Applied Physics A, vol. 94, no. 2, pp. 221-230, August 2009; J. Trice, D. Thomas, C. Favazza, R. Sureshkumar, and R. Kalyanaraman, “Pulsed-laser-induced dewetting in nanoscopic metal films: Theory and experiments,” Physical Review B, vol. 75, no. 23, p. 235439, June 2007; and J. Trice, C. Favazza, D. Thomas, H. Garcia, R. Kalyanaraman, and R. Sureshkumar, “Novel Self-Organization Mechanism in Ultrathin Liquid Films: Theory and Experiment,” Physical Review Letters, vol. 101, no. 1, p. 017802, July 2008]. The most common plasmonic interfaces used for light trapping consists of nanoparticle islands formed through thermal evaporation of a metal film followed by annealing [H. A. Atwater and A. Polman, “Plasmonics for improved photovoltaic devices,” Nature Materials, vol. 9, no. 3, pp. 205-13, March 2010; S. Pillai, K. R. Catchpole, T. Trupke, and M. A. Green, “Surface plasmon enhanced silicon solar cells,” Journal of Applied Physics, vol. 101, no. 9, p. 093105, 2007; and H. R. Stuart and D. G. Hall, “Island size effects in nanoparticle-enhanced photodetectors,” Applied Physics Letters, vol. 73, no. 26, p. 3815, 1998]. Synthesis of plasmonic nanoparticles using colloid chemistry techniques has been examined. [A. M. Eremenko and N. P. Smirnova, “Silver and Gold Nanoparticles in Silica Matrices: Synthesis, Properties, and Application,” Theoretical and Experimental Chemistry, vol. 46, no. 2, pp. 67-86, 2010; and K. L. Kelly, E. Coronado, L. L. Zhao, and G. C. Schatz, “The Optical Properties of Metal Nanoparticles: The Influence of Size, Shape, and Dielectric Environment,” Journal of Physical Chemistry B, vol. 107, pp. 668-677, 2002]. Manufacturing of plasmonic interfaces from nanoparticle suspensions using wet chemistry methods has been examined [T. Cong, S. N. Wani, P. A. Paynter, and R. Sureshkumar, “Structure and optical properties of self-assembled multicomponent plasmonic nanogels,” Applied Physics Letters, vol. 99, no. 4, p. 043112, 2011; and D. Erickson, D. Sinton, and D. Psaltis, “Optofluidics for energy applications,” Nature Photonics, vol. 5, pp. 583-590, September 2011]. Chemically synthesized nanoparticles with controllable size, shape and architecture have been investigated [L. M. Liz-marza, “Synthesis of Nanosized Gold-Silica Core-Shell Particles,” Langmuir, vol. 7463, no. 6, pp. 4329-4335, 1996].